Television * NBC's quiz show takes off quickly, but execs insist they won't flood the schedule with it.

Roughly a year after the rapid demise of those NBC, CBS and Fox game shows--all hastily assembled to emulate, or if nothing else undercut, the popularity of ABC's "Who Wants to Be a Millionaire"--NBC may have cracked the quiz code with "Weakest Link," a British import that drew promising ratings for a trio of telecasts last week.

The question awaiting an answer now, however, is what happens next?

The three maiden installments of "Weakest Link"--including the premiere, in its regular Monday 8 p.m. slot, and extra episodes on Tuesday and Wednesday designed to generate sampling of the series--averaged 15.5 million viewers, with NBC estimating more than 50 million people tuned in for at least a few minutes. NBC is expected this week to order 13 additional episodes, at minimum extending the show's run through the summer.

NBC officials--who vowed before the launch that they would "shoot each other" before getting greedy and deciding to broadcast the show multiple times a week--are clearly thrilled to have a potential hit on their hands, especially heading into the May rating sweeps, which officially begin Thursday.

"We don't want to go overboard," stressed NBC Entertainment President Jeff Zucker. "We are honestly just cautiously optimistic. . . . Monday night at 8 has been a really difficult time period for us, but we've turned the lights on a little bit."

Yet beyond the short-term ratings fix "Weakest Link" could provide in a moribund Monday slot (plus a scheduled Thursday telecast, featuring contestants from the original "Survivor," after "Friends" on May 10), NBC has to wonder about the kind of burnout that can assail instant TV phenomena in general and quiz shows in particular.

Most notably, "Millionaire," once perceived as a franchise destined to keep ABC in prime time's driver's seat for years, faded faster than anyone anticipated, especially among the younger viewers sought by advertisers. While the program continues to do well by almost any standard, its demographics have shifted to a traditional pattern for game shows, such as "Jeopardy!" and "Wheel of Fortune," which heavily skew to an older audience.

At first, "Millionaire" bucked that demographic trend, and so has "Weakest Link." The NBC show opened with a median viewing age of 42, mirroring "Millionaire's" audience profile during its trial run in August 1999. This season--with ABC expanding the series to four editions per week--"Millionaire's" median viewing age has climbed to 54, diminishing its allure to media buyers.

"Millionaire" executive producer Michael Davies said it was too early to gauge "Weakest Link's" long-term potential given the promotional bombardment NBC threw at the project, hammering home host Anne Robinson's dismissive catch phrase, "You are the weakest link. Goodbye," even before viewers got a glimpse of the series.

"This is viral marketing, and I'm not saying that pejoratively. . . . It's been kind of incredible to watch," Davies said.

Unlike last year's aforementioned quiz failures, Davies noted, "Weakest Link" possesses a track record in Britain that put the producers a step ahead in mounting the series. What he questions is whether the play-along element--an important part of the game-show formula--is lost in the show's rapid-fire approach, which places considerable emphasis on the hostile, "Survivor"-like nature of the competition.

"In order for it to have legs, you're going to have to have the audience playing along with the show," Davies said, adding that the emphasis on creating drama and conflict among the contestants "feels a little forced."

Zucker surmised viewers have responded to the show initially for two reasons: the fast pace and Robinson. Based on its performance at 9:30 and 10 p.m. on Tuesday and Wednesday, respectively, he acknowledged the network could move the program to a later hour but reiterated that NBC remains committed to not overexposing it.

"I think that's one of the ways we keep it special," he said.

Zucker also cited some encouraging signs that "Weakest Link" could be somewhat unique among game shows, including "off the charts" success thus far attracting affluent and college-educated viewers, based on a breakdown of Nielsen Media Research data.

"Millionaire," meanwhile, has scheduled another celebrity edition--a stunt that has reliably provided a ratings boost--over five episodes beginning May 6. Since the first celebrity showcase last spring, other networks have sought to prevent their stars from participating, forcing ABC to feature its own talent or performers who don't appear on a rival network. The latest roster includes Jason Alexander, Chevy Chase, Edie Falco, Dennis Franz, John Leguizamo, Kelly Ripa, Martin Short, Kevin Sorbo, Ben Stiller and Alfre Woodard.

Davies said he would continue to invite talent from competing networks to take a turn in the "hot seat" (money raised goes to the star's hand-picked charity) and pointed out Falco is appearing even though "Millionaire" plays directly opposite her HBO series, "The Sopranos," Sunday nights at 9.

As for the heat surrounding any instant prime-time sensation, from "Weakest Link" to "Temptation Island," Davies suggested the hullabaloo inevitably subsides, which is when the challenge facing a producer truly kicks in.

" 'Millionaire' went from being a national phenomenon to just being a television show, which is fine," he said. " 'Survivor' and these [other alternative format] shows are going to have to go through that."